The present invention relates to hitch devices for attaching farm implements to a tractor and, more particularly, to a strut for a farm implement hitch device.
So-called xe2x80x9cthree-point hitchesxe2x80x9d normally comprise a top link and two bottom arms articulated to the tractor frame whereby each bottom arm is connected to a respective hydraulic lifting device. A farm implement, such as a plow or ripper, is fixed by known means to a three-point hitch of the above type.
Hitches of the above type allow the bottom arms to swing laterally when the tractor is moving. Particularly during on-highway transfer and when the implement is raised, lateral swing of the bottom arms is extremely dangerous, and may result in serious damage and/or personal injury caused by collision with the implement and/or hitch components. In such conditions, therefore, steps should be taken to ensure that the hitch and attached implement swing as little as possible. To this end, side struts of a fixed length are provided which operate on the bottom arms of the hitch.
On the other hand, when operating on a field, the strut should act as a stabilizer, since under these conditions it is often necessary to allow the implement to float to a certain extent. In other words, when actually working, it is often preferable to employ, as opposed to an overly rigid implement towing system, one allowing the implement to swing to a certain extent on encountering obstacles (such as stones) in the field.
For this purpose, stabilizing struts have been proposed which are connected, at one end, to the tractor frame, and are fixed at the other end to one of the bottom three-point hitch arms.
Stabilizing struts of this sort provide, in fact, for bracing the implement towing system, e.g. during on-highway transfer of the tractor, while at the same time allowing the three-point hitch and attached implement to swing to a certain extent when working on the field.
The stabilizing struts employed so far, however, fail to provide for reliable adjustment of the degree of rigidity of the implement towing system.
It is therefore an object of the present invention to provide a reliable strut for use in the hitch apparatus of agricultural tractors.
It is a feature of this invention that a strut for a tractor three-point hitch includes a discrete length adjustment mechanism and two infinite length adjustment devices.
It is another feature of this invention that the infinite length adjustment devices are located on opposite sides of a dividing member
It is still another feature of this invention that the infinite length adjustment devices are positioned crosswise to the axis of the strut.
It is an advantage of this invention that the adjustment of the axial length of the strut can be quickly and selectively accomplished.
It is yet another feature of this invention that the adjustment of the length of the strut is accomplished through utilization of a number of through holes in the tubular member of the strut and a number of through holes in the sleeve of the strut.
It is another advantage of this invention that a continuous fine adjustment of the length of the strut can be accomplished at both ends of the strut by manipulation of two rods with respective threaded shanks.
It is still another advantage of this invention that the strut is free to swing within predetermined limits when required.
It is yet another feature of this invention that the tubular member is allowed to float inside a cavity within the strut by lifting the spring member and removing a pin.
It is yet another advantage of this invention that the strut can be preloaded using the fine-adjustment system to eliminate any slack caused by discrete adjustment using the pin.
It is a further advantage of this invention that the degree of float can be adjusted according to the type of work to be performed by the implement attached to hitch device by allowing float on one side of the strut and setting a length at the other side of the strut.
It is another object of this invention to provide a strut apparatus for a three-point hitch mechanism on an agricultural tractor such that the strut may replace the lifting arms of the conventional hitch which are connected to the lower arms of the hitch and which also require a length adjustment mechanism.
These and other objects, features and advantages are accomplished according to the instant invention by providing a strut for a hitch device for attaching farm implements to a tractor. The strut is substantially symmetrical with respect to a longitudinal axis of symmetry, and has a system for adjusting its length along the axis. The adjusting system has fast, discrete length adjustment devices, and two infinite length adjustment devices. The two infinite length adjustment devices are located on opposite sides of a dividing member positioned crosswise to the axis of the strut.